1. Field of the Invention
This invention relates to electromechanical vibrators and, in particular, to a device for driving an electromechanical vibrator.
2. Description of the Invention
In order to stimulate the skin and/or muscle of the human body, an electromechanical vibrator has been used in the prior art. The vibrator is usually driven by application of an A.C. electric current of a constant frequency.
A sound reproducing system has been known in the prior art as disclosed in, for example, U.S. Pat. No. 4,064,376, which reproduces from an electric signal not only sound felt by ear but also mechanical vibration, of preferably undertones lower than 150 Hz, to be directly transmitted to a body. Such a system has an electromechanical vibrator for reproducing the mechanical vibration in addition to sound reproducing speakers. An audio signal is fed to not only the speakers but also the vibrator which is fitted to a bed or a chair. The audio signal is preferably passed through a filter for removing a higher frequency component than 150 Hz and thereafter, is applied to the vibrator. A person on the chair or bed receives rhythmical stimulus to his body while enjoying music from the speaker through ear. Accordingly, he may feel better than use of the conventional electromechanical vibrator generating vibration of a constant frequency.
However, in use of the sound reproducing system for stimulating the body, the user is always forced to listen to a music.